Study on the Dispersion Mechanism of Polymer-Added Slurry via the Solid Kneading Process

Abstract

In this study, we investigated the effect of kneading on particle dispersion in aqueous carbon slurries used for the manufacture of lithium-ion battery anodes. Kneading, a method involving the preparation of slurry with a high particle concentration followed by dilution, is traditionally recognized as a technique to enhance particle dispersion. To evaluate this process, slurries with varying particle concentrations during kneading were prepared, and their characteristics were analyzed. Our findings revealed contrasting effects depending on the type of carbon material. For acetylene black slurries, increasing the particle concentration during kneading reduced the relative viscosity and improved particle dispersion. However, in graphite slurries, the addition of carboxymethyl cellulose (CMC) and subsequent kneading resulted in particle agglomeration. These results indicate that kneading does not always enhance dispersion and may, under certain conditions, even lead to agglomeration. This study highlights the need to reevaluate the conventional approach to kneading, suggesting that the process parameters should be carefully optimized to suit the specific materials and applications.